Google Penguin is a code name for a Google algorithm update that was first announced on April 24, 2012. The update is aimed at decreasing search engine rankings of websites that violate Google’s Webmaster Guidelines by using black-hat SEO techniques, such as keyword stuffing, cloaking, participating in link schemes, deliberate creation of duplicate content, and others.

Infographic:
The compiled list of 100 domains that were directly affected by the Penguin 3 update: 50 Winners vs. 50 Losers. Both groups are analyzed to find out exactly what happened.

You can get answers to the following questions:

Is this all just a conspiracy to sell Google Adwords?

Are footer links a cause of a Penguin penalty?

Does the age of my domain play a role in this update?

How important is link velocity (AKA link growth)?

What about the number of linking root domains (domain popularity)?

Does the number of indexed pages of a site decide between winners and losers?

Are site-wide links a factor in the Google Penguin 3 update?

Does the hosting country of my site matter?

Does it matter from which country my links come from?

Do social shares help boost rankings?

How can TitleRank be used in the post-penguin era? and what does it tell?

What does Power*Trust have to do with it?

How does Google look at the Deep Link Ratio site?

Are big sites with a lot of rankings in favor over small ones with only a few?

How does Alexa as a traffic indicator matter in the Penguin 3 update?

Google has been telling us that Penguin targets webspam and it will reward high-quality site. How can we measure “high-quality”?

Penguin’s effect on Google search results
By Google’s estimates, Penguin affects approximately 3.1% of search queries in English, about 3% of queries in languages like German, Chinese, and Arabic, and an even bigger percentage of them in “highly-spammed” languages. On May 25th, 2012, Google unveiled the latest Penguin update, called Penguin 1.1. This update, according to Matt Cutts, was supposed to impact less than one-tenth of a percent of English searches. The guiding principle for the update was to penalise websites using manipulative techniques to achieve high rankings. Penguin 3 was released Oct. 5, 2012 and affected 0.3% of queries